Free-space optical (FSO) communication is an optical communication technology that employs light propagating in free space to transmit data for telecommunications and/or computer networking. “Free space” can mean air, outer space, a vacuum, water, etc. FSO contrasts with using a solid medium such as optical fiber cable or an optical transmission line that constrains the dispersion of photons. FSO can be useful where physical connections are impractical due to high costs and/or other considerations.
Quality of service (QoS) can refer to several related aspects of computer networks that allow the transport of network traffic with specific parameters. In particular, much technology has been developed to allow computer networks to become as useful as telephone networks for audio and/or video conversations, as well as supporting new applications with strict service demands, such as video on demand services.